2-O-Acetyltenuiorin, a new tridepside from the lichen Pseudocyphellaria australiensis

Abstract

The tridepside 2-O-acetyltenuiorin (4) has been isolated from the lichen Pseudocyphellaria australiensis.  The structure of this compound followed from spectroscopic data and was corroborated by permethylationwith diazomethane to give methyl 2-0-acetyl-2',2"-di-O-methylgyrophorate (5). Total synthesis of 2-O-acetyltenuiorin confirmed the assigned structure. This new tridepside was also shown to occur in several other Pseudocyphellaria species as well as two Peltigera species.